The invention relates to an adjustment device for producing a two-sided rotational movement.
From German Patent Application Publication No. DE 199 07 483 an adjustment device acting on two sides for producing a rotational movement is known which has a housing in which are mounted a drive element and an output element which can be adjusted angularly through actuation of the drive element, as well as a loop spring which is supported at least partially on the inside wall of the housing and thereby blocks torque introduced on the output side and is contracted when torque is introduced on the drive side and thereby releases the transfer of torque from the drive element to the output element. The ends of the loop spring are connected to a transfer element which is mounted between the drive element and the output element and has a base body mounted circular segment shape round the axis of the output element. To reduce the play during transfer of torque from the drive element to the output element the housing tapers towards the axis of the output element whilst the transfer element or loop springs are pretensioned axially towards the reducing housing diameter.
The drive element can in the case of the known adjustment device be provided additionally with a radially or circumferentially guided compensating element which bears free of play against the stop faces of the transfer element and consists of two scissor levers which are displaceable opposite one another in the circumferential direction, as well as of a radially spring-loaded wedge slider which is disposed between the scissor levers and is mounted in a guide of the drive element, wherein the wedge slider is provided with a central spring-loaded wedge guide guided in the guide of the drive element so that its radial displacement in the guide of the drive lever exerts a circumferentially acting force on the scissor lever and thereby ensures sufficient freedom of play.
An adjustment device of this kind is suitable both for transferring torque on the drive side from a drive element to a driven element and also as a brake lock for blocking torque introduced from the output side of the adjustment device. The use of a loop spring as force transfer element for transferring the adjustment movement of the drive element to the driven element or as brake element for blocking an output-side torque by expanding the loop spring and producing a block through the cylindrical contact face of the loop spring bearing against a locally-fixed adjustment housing, requires precision matching of the force transfer elements in order on the one hand to ensure the maximum possible play-free force transfer from the drive element to the driven element and a secure blocking of the torque introduced on the output side as soon as this is greater than or equal to the torque introduced on the drive side.
A further problem lies in moving the drive element reliably back into the neutral starting position after an adjustment movement has been made and when the adjustment system is relaxed without thereby triggering any unintended adjustment of the adjustable mechanism of a motor vehicle connected to the adjustment device.
Since adjustment devices of this kind are now used in greater numbers attempts are made to lower the production costs whilst providing lower manufacturing and installation expense and lighter weight for installation in a motor vehicle.
The object of the present invention is to provide an adjustment device of the type mentioned at the beginning which with the same functioning principle is suitable both for a drive and for a brake lock, enables simple mounting of the spring element and guarantees good force transfer between the drive element and the driven element or ensures secure blocking of torque introduced on the output side and reliable resetting of the function elements of the adjustment device into the neutral starting position independently of the spring force of the spring element.